The mechanisms of outflow of aqueous humor and the structural details of the tissues involved in that mechanism are controversial. This problem will be addressed through a tri-directional investigation. The primary goal of these investigations is to clarify the structural and functional correlates of aqueous outflow in the developing and adult eye of higher primates. Additionally, it is hoped that insights may be gained into the phylogenetic background of the aqueous outflow system. Information derived from such studies may well contribute toward the prevention and/or cure of glaucoma in man. First, the functional significance of the unique structural character of the primate aqueous outflow system will be examined by comparing parameters of aqueous outflow and accommodative amplitude in primates, non-primate mammals, and birds. These will be correlated with the structural characteristics of tissues involved in the drainage of aqueous humor. Secondly, interrelationships of physiologic factors effecting facility of aqueous outflow will be examined by quantitative constant pressure aqueous perfusion in living monkeys and non-primate mammals. Thirdly, the developmental changes in the dynamics of aqueous outflow will be investigated by constant pressure quantitative aqueous perfusion in postmortem eyes from fetal and neonatal monkeys. In correlation with these functional studies, structural investigations including microvascular castings and detailed light and electron microscopic (transmission and scanning) evaluation will be made of specimens of the aqueous outflow system from eyes perfused in the experiments outlined above.